Avoid Common Mistakes when Building an Outdoor Arena

Plan ahead when designing and building an outdoor arena, and seek professional assistance if you're unsure of how to proceed for the best results.

Photo: Erica Larson, News Editor

There are many common mistakes that you can easily avoided when building an equestrian arena. Here are a few of the major pitfalls that sometimes arise when either building an arena or having one constructed, along with tips on how to avoid them.

Using the wrong quantity or quality of stone in the base layer.

Know in advance what type of materials will be required for your build and what you're being supplied with. For the base—a stone drainage layer—it's vital to use clean, hard, angular stone. Some tips to remember:

Ensure the stone you choose has been washed so dust and/or fine soil doesn't run straight in to your drains, causing reduced drainage.

Choose stones that are frost resistant (i.e., will not break down after successive winters) and will not fracture under the weight of maintenance machinery, like tractors. Granite or hard limestone (not soft limestone) are good base layer options.

Seek out angular stones that are around the same size—typically 1 ¾ to 2 ¾ inches in size—that will "knit" together to solidify the base. If the base layer contains rounded stones that can't knit together and can shift below the surface, your arena surface will never be correctly compacted.

Make your stone layer about 5 inches thick when compacted. Ideally the stone layer should extend about 20 inches beyond the fence/kick boards so the perimeter drain can be laid outside the school.

Be cautious if your contractor does not specify the grade/quantity or depth of the base materials being laid. If contractors use less stone and lay a thinner base, the project will cost less, and some contractors might use this lower cost to their advantage to win the work with a smaller price tag than other companies.

If you're choosing a base layer yourself, the quarry can provide technical data sheets about the stones you're considering if you have any doubt that you're selecting the correct product for the job.

Installing inadequate drainage.

You should have at least one drain running across the arena and one around its perimeter. These perimeter drains are important because the outside track typically accommodates the largest amount of traffic. If the ground is heavy clay, you'll likely need to install additional cross-drains and increase the diameter of the exterior drains to ensure proper drainage.

Additionally, ensure the tops of all the drain trenches are covered with a fine-grade (i.e., 4 ounce) nonwoven geotextile membrane, which will allow the water to pass in to the drains but prevent silt or sediment from entering the drains.

Choosing weak fencing posts.

Always concrete your arena's fence posts into the ground, as they need to support the retaining boards, withstand the surface being packed against them, and be able to endure being struck by maintenance machinery.

Building at the wrong time of year or in the wrong conditions.

Plan ahead before you start building your arena. Choose a dry period, preferably in the summer, to begin construction.

Clay, in particular, needs to be carefully managed so “clay heave” does not occur—this is most likely to happen when it's wet and under pressure, which causes it “bubble up.” This can ultimately move the stone base layer and result in footing problems and poor drainage. Should this occur, remedial works will be required.

Take-Home Message

Plan ahead when designing and building an outdoor arena, and seek professional assistance if you're unsure of how to proceed for the best results.

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